System and Method of Radio Bearer Management for Multiple Point Transmission

ABSTRACT

A method for operating a multiple point transmission system is disclosed. The method includes reconfiguring the multiple point transmission system according to an updated configuration of an at least one radio bearer between an at least one transmission point and a terminal device, and communicating with the terminal device using the reconfigured multiple point transmission system. The configuration of the at least one radio bearer is updated according to operating condition information of the terminal device.

TECHNICAL FIELD

The present invention relates to a system and method for setting upradio bearers in a wireless communication, and more particularly to asystem and method for multiple point transmission in a wirelesscommunications system.

BACKGROUND

Wireless communication systems have become an important means by whichmany people worldwide have come to communicate. A wireless communicationsystem interconnects many nodes by using electromagnetic waves, such asradio waves, rather than wires commonly used in a fixed telephonenetwork system. A wireless communication system often consists of manymobile devices and a plurality of base stations. A base station serves amobile device when it enters a region associated with the base station.

Wireless communication systems are widely used to provide voice and dataservices for multiple users using a variety of access terminals such ascellular telephones, laptop computers and various multimedia devices.Such communications systems can encompass local area networks, such asIEEE 801.11 networks, cellular telephone and/or mobile broadbandnetworks. The communication system can use one or more multiple accesstechniques, such as Frequency Division Multiple Access (FDMA), TimeDivision Multiple Access (TDMA), Code Division Multiple Access (CDMA),Orthogonal Frequency Division Multiple Access (OFDMA), Single CarrierFrequency Division Multiple Access (SC-FDMA) and others. Mobilebroadband networks can conform to a number of standards such as the main2^(nd)-Generation (2G) technology Global System for MobileCommunications (GSM), the main 3^(rd)-Generation (3G) technologyUniversal Mobile Telecommunications System (UMTS) and the main4^(th)-Generation (4G) technology Long Term Evolution (LTE).

As technologies evolve, multiple input, multiple output (MIMO) systemsare employed to achieve better channel utilization and overallperformance. In particular, MIMO systems are communication systemshaving multiple transmission and multiple reception antennas at bothenhanced Node B (eNB) (or base station (BS), Node B (NB, and so forth)and user equipment (UE) (or mobile station (MS), terminal, terminaldevice, user, subscriber, subscriber equipment and so on). In a MIMOsystem, a transmitter may transmit a multiple user MIMO signals to aplurality of receivers. Each of the MIMO signals may be pre-coded with acorresponding pre-coding scheme. In addition, the MIMO signals may bespatially multiplexed and transmitted in the same time-frequency slot.

An extension to MIMO makes use of multiple transmission points (each ofwhich may be a set of geographically co-located transmit antennas) totransmit to a single UE or a group of UEs. The transmissions from themultiple transmission points may occur at different times and/or atdifferent frequencies so that the UE (or the group of UEs) will receivetransmissions from all of the multiple transmission points over a timewindow. This operating mode may often be referred to as multiple pointtransmission. As an example, at a first time, a first transmission pointmay be employed to transmit data to a UE, at a second time, a secondtransmission point may be employed to transmit data to the UE, and soon.

Coordinated multiple point (CoMP) transmission is one form of multiplepoint transmission, wherein the transmission made by the multipletransmission points are coordinated so that the UE or the group of UEmay be able to either combine the transmissions made by the multipletransmission points or avoid interference to improve overallperformance. A transmission point may be an eNB, a part of an eNB, aremote radio head coupled to an eNB and the like. When the UE transmitsdata to an eNB, a CoMP based reception means the transmitted data fromthe UE will be received by a plurality of geographically separated eNBs.On the other hand, when the UE receives data, the data to the UE may beinstantaneously transmitted from a plurality of transmission points.

As an extension to multiple point transmission systems, coordinatedmultiple point (CoMP) transmission and reception is adopted for LongTerm Evolution Advanced (LTE-A) to further improve channel utilizationand overall performance. CoMP helps to enable the dynamic coordinationof transmission and reception of a plurality of base stations. Moreparticularly, when a mobile station is located at an overlapped regionloosely covered by a plurality of base stations, CoMP helps tocoordinate the base stations so that the base stations are able tojointly transmit user data to the mobile station. In addition, through adynamic base station selection scheme, CoMP helps to find a base stationand enable the base station to transmit user data to the mobile station.In order to better coordinate a plurality of base stations serving amobile station, the channel property feedback information such aschannel status information from mobile stations to a network entity isrequired.

CoMP transmission has been considered as a fundamental element for thenext generation wireless communications systems. For example, in ThirdGeneration Partnership Project (3GPP) Long Term Evolution Advancedstandards compliant communications systems, CoMP transmission is aneffective tool to improve the coverage of high data rates, cell-edgethroughput, and/or to increase overall communications system throughputin both high load and low load scenarios. As such, by employing CoMP, aLTE-A system may achieve better coverage and capacity.

SUMMARY OF THE INVENTION

These technical advantages are generally achieved by the presentinvention which provides a system and method for managing radio bearersin a multiple point transmission system.

In accordance with an embodiment, a method includes reconfiguring themultiple point transmission system according to an updated configurationof an at least one radio bearer between an at least one transmissionpoint and a terminal device, and communicating with the terminal deviceusing the reconfigured multiple point transmission system. Theconfiguration of the at least one radio bearer is updated according tooperating condition information of the terminal device.

In accordance with another embodiment, a system comprises a primarypoint and an at least one secondary point. The at least one of theprimary point and the at least one secondary point is configured toreconfigure the multiple point transmission system according to anupdated configuration of an at least one radio bearer between an atleast one transmission point and a terminal device, and communicate withthe terminal device using the reconfigured multiple point transmissionsystem. The configuration of the at least one radio bearer is updatedaccording to an operating condition information of the terminal device.

In accordance with another embodiment, a primary point for operating amultiple point transmission system is disclosed. The primary pointincludes a processor and a transceiver. The processor is configured todetermine that a reconfiguration is needed for the multiple pointtransmission system. The reconfiguration is in accordance with anupdated configuration of an at least one radio bearer between at leastone transmission point and a terminal device and the configuration isupdated according to operating condition information of the terminaldevice. The transceiver is configured to inform a terminal device bysending a first message regarding the reconfiguration.

In accordance with another embodiment, a multiple point transmissionsystem is disclosed. The multiple point transmission system includes aprimary point and at least one secondary point. The primary point isconfigured to communicate with a terminal device and to inform theterminal device regarding an updated configuration of an at least oneradio bearer associated with the multiple point transmission system. Theat least one secondary point is configured to communicate with theterminal device and at least one of the at least one secondary point iscapable of scheduling downlink data transmission to the terminal deviceindividually. The multiple point transmission system further includes acontroller. The controller is configured to reconfigure the multiplepoint transmission system according to the updated configuration of theat least one radio bearer.

An advantage of an embodiment of the present invention is enabling anefficient multiple point transmission between a plurality of wirelesspoints and a terminal device.

The foregoing has outlined rather broadly the features and technicaladvantages of the present invention in order that the detaileddescription of the invention that follows may be better understood.Additional features and advantages of the invention will be describedhereinafter which form the subject of the claims of the invention. Itshould be appreciated by those skilled in the art that the conceptionand specific embodiment disclosed may be readily utilized as a basis formodifying or designing other structures or processes for carrying outthe same purposes of the present invention. It should also be realizedby those skilled in the art that such equivalent constructions do notdepart from the spirit and scope of the invention as set forth in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and theadvantages thereof, reference is now made to the following descriptionstaken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a data path in a LTE wireless network in accordancewith an embodiment;

FIG. 2 illustrates a block diagram of packets transport through radiobearers in accordance with an embodiment;

FIG. 3 illustrates a plurality of coordinated multiple pointtransmission (CoMP) communication systems in accordance with anembodiment;

FIGS. 4 illustrates an example logical view of a communication systemcomprising a CoMP cooperating set and a CoMP controller in accordancewith an embodiment;

FIG. 5 illustrates a logical UE connection to Serving Gateway (SGW) andMobility Management Entity (MME) through a CoMP controller using S1-Uand S1-MME interfaces in accordance with an embodiment;

FIG. 6 illustrates an example of configuring radio bearers over multipletransmission points in accordance with an embodiment;

FIG. 7 illustrates the signaling flow of a method for managing radiobearers in a CoMP system in accordance with an embodiment;

FIG. 8 illustrates a simplified block diagram of a CoMP controller thatcan be used to implement the radio bearer management method inaccordance with an embodiment; and

FIG. 9 illustrates a simplified block diagram of a primary point incommunicating with a CoMP controller and a UE in accordance with anembodiment.

Corresponding numerals and symbols in the different figures generallyrefer to corresponding parts unless otherwise indicated. The figures aredrawn to clearly illustrate the relevant aspects of the variousembodiments and are not necessarily drawn to scale.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The making and using of the presently preferred embodiments arediscussed in detail below. It should be appreciated, however, that thepresent invention provides many applicable inventive concepts that canbe embodied in a wide variety of specific contexts. The specificembodiments discussed are merely illustrative of specific ways to makeand use the invention, and do not limit the scope of the invention.

The present invention will be described with respect to preferredembodiments in a specific context, namely a system and method formanaging radio bearers in a multiple point transmission system.Furthermore, the invention may also be applied to a variety ofcommunication systems.

Referring initially to FIG. 1, a data path in a LTE wireless network isillustrated in accordance with an embodiment. The wireless network mayinclude a wireless user equipment (UE) 102 and an IP network 122. The UEdevice 102 communicates with the IP network 122 through a data pathformed by a plurality of functional elements such as Enhanced UMTS RadioAccess Network (E-UTRAN), Serving Gateway, Packet Data Network (PDN)Gateway and the like. The wireless network may further comprise otherfunctional elements such as a Mobility Management Entity (MME) node 112.The MME is capable of authenticating a user through a home subscribersystem (HSS) 114.

The UE device 102 may be a notebook computer, a mobile phone or aPersonal Digital Assistant (PDA), a media player, a gaming device or thelike. The E-UTRAN 104 may comprise a plurality of base stations such aseNodeB in a LTE wireless system. Each base station may include aprocessor, a transmitter and a receiver. Furthermore, the transmittermay comprise at least one transmit antennas. The receiver may compriseat least one receive antenna. Similarly, the UE 102 may include aprocessor, a transmitter and a receiver. In addition, the transmitter ofthe UE 102 may comprise at least one transmit antenna. The receiver ofthe UE 102 may comprise at least one receive antenna.

The SGW 116 is employed to route and forward data packets between the UE102 and the PDN Gateway 118. In addition, the SGW 116 functions as amobility anchor between a LTE based wireless system and other 3GPPsystems such as GSM and UMTS. PDN Gateway 118 is employed to provide anexit and entry point between the UE 102 and external data networks suchas operator's IP network 122. By employing a policy and charging rulefunction (PCRF) device 120, PDN Gateway 118 may provide a plurality offunctions for the UE 102 such as policy enforcement, data packetscreening, data packet filtering, data packet interception and the like.In addition, the PDN Gateway 118 may function as a mobility anchorbetween a 3GPP system such as a LTE system and a non-3GPP system such asWiMAX, 3GPP2 or the like.

FIG. 2 illustrates a block diagram of packets transport through radiobearers in accordance with an embodiment. The data transport may beimplemented by using Evolved Packet System (EPS) bearers formed betweenthe UE 102 and the PDN Gateway 118. EPS provides connectivity between aUE (e.g., UE 102) and an external data network (e.g., operator's IPnetwork shown in FIG. 1). An EPS bearer may comprise a radio bearer, anS1 bearer and an S5/S8 bearer. As shown in FIG. 2, a radio bearer 202carries the data transport between the UE 102 and the eNB 204. An S1bearer 206 carries the data transport between the eNB 204 and the SGW116. Furthermore, an S5/S8 bearer 208 carries the data transport betweenthe SGW 116 and PDN gateway 118.

In the UE 102, UL-TFT maps an uplink traffic flow aggregate to an EPSbearer in the uplink direction. More particularly, as shown in FIG. 2,there may be a one-to-one mapping (e.g., UL-TFT→RB-ID) between an EPSbearer and a radio bearer. Likewise, in the PDN gateway 118, DL-TFT mapsa traffic flow aggregate to an EPS bearer in the downlink direction. Inparticular, the PDN Gateway may include a one-to-one mapping (e.g.,DL_TFT→S5/S8-TEID) between a downlink packet filter and an S5/S8 bearerto create the mapping between a traffic flow aggregate and an S5/S8bearer in the downlink. Furthermore, in the eNB 204, there may be aone-to-one mapping (e.g., RB-ID⇄S1-TEID) between a radio bearer (e.g.,radio bearer 202) and an Si bearer (e.g., Si bearer 206) to create thebinding between a radio bearer and an Si bearer in both the uplink andthe downlink directions. Likewise, in the SGW 116, there may be aone-to-one mapping (e.g., S1-TEID⇄S5/S8-TEID) between an S5/S8 bearerand an S1 bearer to create the binding between an S5/S8 bearer and an S1bearer in both the uplink and the downlink directions.

FIG. 3 illustrates a plurality of coordinated multiple pointtransmission (CoMP) communication systems in accordance with anembodiment. The CoMP Communication systems 300 may comprise a pluralityof eNBs (e.g., eNB 302, eNB 304 and eNB 306) and a plurality of remoteradio units (RRU) such as RRU 312, RRU 314, RRU 316, RRU 422, RRU 324,RRU 326, RRU 332, RRU 334 and RRU 336. Communication systems 300 mayfurther include a plurality of UEs (e.g., UE 342, UE 344, UE 346 and UE348). The UEs may be served by one or multiple eNBs. Alternatively, theUE may be served by one or more RRUs. Furthermore, the UE may be servedby a combination of eNBs and RRUs. A CoMP communication system comprisesone UE and multiple transmission points, wherein a transmission pointmay be an eNB, a part of an eNB, a RRU and the like.

For example, UE 342 may be served by RRU 312, RRU 314 and RRU 316. As aresult, UE 342, RRU 312, RRU 314 and RRU 316 form a first CoMPcommunication system. On the other hand, UE 344 may be served by RRU322, RRU 324 and RRU 326. Similarly, UE 344, RRU 322, RRU 324 and RRU326 form a second CoMP communication system. As shown in FIG. 3, UE 346may be served by RRUs (e.g., RRU 326 and RRU 332) controlled bydifferent eNBs (e.g., eNB 304 and eNB 306). More particularly, eNB 304controls RRU 326 and eNB 306 controls both RRU 332 and RRU 334. Inaddition, RRU 336, RRU 332 and RRU 334 serve the UE 348. RRU 336, RRU332, RRU 334 and UE 348 form a third CoMP communication system.

There may be a plurality of transmission points within a CoMP system. Inaccordance with an embodiment, a transmission point may be referred toas a primary point. The remaining transmission points may be referred toas secondary points. The primary transmission point may be considered tobe a controlling transmission point for a UE, responsible for exchangingcontrol signal messages (e.g., radio resource control messages) with theUE.

It should be noted that while FIG. 3 uses eNBs as communicationscontrollers. Other types of communications controllers may be used inplace of or in conjunction with eNBs. For example, Base Stations, LowPower Nodes, femto cells, pico cells and the like, may be used asreplacements of or in conjunction with eNBs. Therefore, the discussionof eNBs should not be construed as being limiting to either the scope orthe spirit of the example embodiments.

Furthermore, the discussion presented herein focuses on CoMPtransmission. However, the example embodiments presented here are alsooperable with a more general form of CoMP transmission, i.e., multiplepoint transmission. Therefore, the discussion of CoMP transmissionshould not be construed as being limiting to either the scope or thespirit of the example embodiments.

FIG. 4 illustrates an example logical view of a communication system 400comprising a CoMP cooperating set and a CoMP controller in accordancewith an embodiment. The communication system 400 may comprises a CoMPcooperating set 402, a CoMP controller 404, an MME pool 406 and a SGWpool 408. The CoMP cooperating set 402 may further comprise a pluralityof eNBs. As shown in FIG. 4, a CoMP controller 404 may be viewed as acentralized control unit of the CoMP cooperating set 402. CoMPcontroller 404 may provide a unified control for setting up, configuringCoMP transmissions for radio bearers, coordinating the operation ofmultiple transmission points with CoMP cooperating set 402 and so on.CoMP controller 404 may be realized as a separate physical entityconnecting all (existing as well as potential) transmission points ofCoMP cooperating set 402. Alternatively, CoMP controller 404 may be alogical function co-located within an existing network entity (e.g., oneof eNBs or one of MMEs). It should be noted that the CoMP controller canbe implemented in hardware, software, firmware and any combinationthereof. It should further be noted that if the CoMP controller isimplemented in software, the software can be stored on computer-readablemedia.

The mobility management entity (MME) pool 406 may be responsible forproviding MMEs that may be used for radio bearer activation and/ordeactivation, as well as UE tracking and paging procedures. MME pool 406may include a plurality of MMEs that may be assigned to a CoMPcontroller (e.g., CoMP controller 404) or an eNB when the CoMPcontroller or the eNB has a need for radio bearer management, and so on.Assigned MMEs may be released once they are no longer needed.

The serving gateway (SGW) pool 408 may be responsible for providing SGWsthat may be used as point of entry and/or exit for traffic to or from aUE. SGW pool 408 may include a plurality of SGWs that may be assignedwhen needed and released when no longer needed.

The communication system 400 may comprise a plurality of logicinterfaces between the CoMP controller 404 and the MME pool 406 as wellas the SGW pool 408. As shown in FIG. 4, there may be a plurality ofS1-MME logical interfaces between CoMP controller 404 and the MME pool406. Likewise, there may be a plurality of S1-U logic interfaces betweenCoMP controller 404 and the SGW pool 408.

FIG. 5 illustrates a block diagram of a logical UE connection to SGW andMME through a CoMP controller using S1-U and S1-MME interfaces inaccordance with an embodiment. As shown in FIG. 5, a UE 502 iswirelessly coupled to an eNB 504. The eNB may be coupled to SGW 508 andMME 510 through a CoMP controller 506. The CoMP controller 506 providesdata exchange between the eNB 504 and SGW 508.

FIG. 6 illustrates an example of configuring radio bearers over multiplepoint transmission system in accordance with an embodiment. The multiplepoint communication system 600 may comprise a primary point 602, asecondary point 604 and a UE 606. The primary point 602 is a point fromwhich UE 606 receives specific control signaling messages including itspaging and/or radio bearer configuration. The other points in a CoMPcooperating set are referred to as secondary points (e.g., secondarypoint 604), which contribute to the data transmission from the networkentities to the UE 606. Under a specific multiple point transmissionconfiguration, usually, both the primary point 602 and the servingsecondary point in the transmission, such as the secondary point 604,may exchange data with the UE 606 through distinct radio bearers.

As shown in FIG. 6, there may be a message exchange path between theprimary point 602 and the UE 606. In addition, there may be a messageexchange path between the primary point 602 and the secondary point 604.After primary point 602 and UE 606 may exchange messages such as thechannel information of the UE 606, the primary point 602 may exchangethe connection configuration messages between the UE 606 and the primarypoint 602 to inform UE 606 of changes to its radio bearer configurationand/or CoMP cooperating set. Furthermore, primary point 602 andsecondary point 604 may exchange coordination configuration messagesdirectly or indirectly (e.g., through a CoMP controller). For example,the messages exchanged between the primary point 602 and the secondarypoint 604 may include adding or removing a radio bearer from one point.As an example shown in FIG. 6, radio bearer 1 is set up between the UEand the primary point and radio bearer 2 is set up between the UE andthe secondary point. Both primary point 602 and secondary point 604 maytransmit data to UE 606 over radio bearer 1 and radio bearer 2respectively. The detailed operation of the CoMP controller will bedescribed below with respect to FIG. 7.

FIG. 7 illustrates the signaling flow of a method for managing radiobearers in a CoMP system in accordance with an embodiment. The methodcomprises updating a configuration of an at least one radio bearer,i.e., one or more radio bearers, between multiple transmission pointsand a terminal device to form an updated configuration based uponoperating condition information of the terminal device, reconfiguringthe multiple point transmission system to form a reconfigured multiplepoint transmission system based upon the updated configuration of the atleast one radio bearer and sending data to the terminal device using thereconfigured multiple point transmission system. As shown in FIG. 7, themethod may include the following steps:

Step 1: a UE reports channel information of nearby points to the primarypoint of the UE. Channel information may include information such asReference Signal Received Power (RSRP) and the like. The RSRP may be anindication of the channel condition between a point and the UE.

The measured channel information may be sent to a network entity. Inaccordance with an embodiment, the network entity may be a CoMPController coupled to the primary point. In various embodiments of theinvention, the CoMP Controller may be located in the primary point, amobility management entity node, or other network entity. Based upon themeasured channel information and desired Quality of Service (QoS) anddata delivery characteristics of the data traffic, the CoMP Controllerdetermines the appropriate setting of one or more radio bears in a CoMPtransmission, including the points to carry the radio bear and the QoSand/or Radio Resource Management (RRM) parameters of radio bearers fromthe involved points.

Step 2: If measured channel information leads to a decision that theremay be a change of the CoMP configuration of the UE, the CoMP controllermay update the CoMP transmission system configuration. In accordancewith an embodiment of the invention, the update may include one or moreof:

1) Adding a point into the CoMP transmission;

2) Removing a point from the CoMP transmission;

3) Adding a radio bearer to a transmission point; and

4) Removing a radio bearer from a transmission point.

In various embodiments of the invention, the CoMP controller may add anew radio bearer to or remove an existing radio bearer from a secondarypoint. The CoMP controller may also add a new secondary point into theCoMP transmission operation and add a radio bearer to the new secondarypoint, or remove radio bearers from an existing secondary point andremove the secondary point from the CoMP transmission operation. TheCoMP controller may also move a radio bearer between two transmissionpoints, e.g., between the primary point and a new or existing secondarypoint, or between two secondary points (new or existing). The moving ofa radio bearer may be done by removing the radio bearer associated withan EPS bearer from the old transmission point, and adding a radio bearerassociated with the same EPS bearer to the new transmission point. Notethat the radio bearer at the old transmission point and the radio bearerat the new transmission point may or may not share the same radio beareridentity, but both radio bearers are associated with the same EPSbearer. It should be noted that usually adding a radio bearer to a newtransmission point is taken place before removing a radio bearer from anexisting transmission point. However, in some embodiment, it is alsopossible to remove a radio bearer from an existing transmission pointfirst and then to add a radio bearer to a new transmission point.

After determining the type of the CoMP transmission configuration, theCoMP controller may either establish configurations for a subset of theat least one radio bearer as new radio bearers or modify existingconfigurations for a subset of the at least one radio bearer.Furthermore, a person skilled in the art will recognize thatalternatively, the CoMP controller may generate a new configuration byestablishing configurations for a subset of the at least one radiobearer as new radio bearers, modifying existing configurations for asubset of the at least one radio bearer, or a combination thereof.

The CoMP Controller may send a CoMP Configuration Request message to theinvolved points. The CoMP configuration request message may include therequested QoS/RRM parameters in correspondence with the type of the CoMPtransmission configuration determined by the CoMP controller. In anembodiment of the invention, the set of parameters, such as therequested QoS/RRM parameters, may include only one parameter or moreparameters. For example, only a QoS parameter is included in the CoMPConfiguration Request message, or a RRM parameter is included in theCoMP Configuration Request message, or only a set of QoS parameters isincluded in the CoMP Configuration Request message, or only a set of RRMparameters is included in the CoMP Configuration Request message, or aset of mixed QoS and RRM parameters is included in the CoMPConfiguration Request message. It can be understood that differentinvolved points may have different types of transmission configurations.The different types of transmission configuration may be reflected by,for example, different priority levels of QoS and/or different set ofRRM parameters. In accordance with an embodiment of invention, theprocedure of determining the CoMP transmission configuration and sendinga CoMP Configuration Request message to different involved points may beseparate. For example, CoMP controller may send a first CoMPConfiguration Request message to a first involved point/points once theconfiguration is determined for the first involved point/points whiledetermining the CoMP transmission configurations for other involvedpoint or points. In various embodiments of the invention, the involvedpoints may be primary point and/or secondary point/points. In a specificexample embodiment as shown in FIG. 7, the involved points may be thesecondary point. It should be noted that the specific embodiment asshown in FIG. 7 is merely illustrative of a specific way to make and usethe invention, and do not limit the scope of the invention.

Step 3: The involved point, e.g., the secondary point in FIG. 7,receives the requested QoS/RRM parameters from the CoMP controller. Inan example embodiment of the invention, there may be already radiobearer(s) existing between the secondary point and the UE or may not atthis stage. If the requested QoS/RRM parameters are acceptable, thesecondary point may respond with a CoMP Configuration Accept message. Inan example embodiment of the invention, the involved point, e.g., thesecondary point in FIG. 7, may verify the availability of its resourceto determine whether the received parameters are acceptable. In anotherembodiment of the invention, the secondary point may make the receivedparameters as lowest requirement and provide better service than thereceived parameters requested, and determine that the receivedparameters are acceptable. For example, the secondary point mayestablish/reconfigure radio bearer with higher priority levels of QoSand/or more efficient RRM parameter, and respond with a CoMPConfiguration Accept message.

Step 4: After receiving the CoMP Configuration Accept message from thesecondary point, the CoMP Controller then instructs the primary point byusing a CoMP Radio Bearer Configuration Request message. The CoMP RadioBearer Configuration Request message includes the information of theradio bearers to be reconfigured. In an example embodiment of theinvention, the CoMP Radio Bearer Configuration Request message mayinclude:

1) The identities of the radio bearers associated with the CoMPreconfiguration;

2) The identities of the associated EPS bearers;

3) The identities of the points to carry this radio bearers (e.g., theradio bearers on the primary point or on the secondary point); and

4) The configuration of how this radio bearer should be transmitted onthe involved point. It should be noted that in some embodiments, forexample, when the configuration does not need to be changed or the radiobearer is configured to be removed, the configuration information maynot necessarily be included in the message.

Step 5: The primary point sends a CoMP Configuration Request message toinstruct the UE the change of the CoMP transmission. The CoMPConfiguration Request message may include the identities of the involvedpoints, radio bearers and EPS bearers. The CoMP Configuration Requestmessage may further include the associated radio bearer configurationparameters and some specific security parameters such as Next hopChaining Counter (NCC).

Step 6: From the received CoMP Configuration Request message, the UEknows the configuration change of the data packet transmission. Moreparticularly, for example, in accordance with a set of specified radiobearer configuration parameters, the UE knows that data packets of theindicated EPS bearer will be transported on the indicated radio bearerfrom the involved point (e.g., a secondary point newly added into themultiple point transmission system) using the specified radio bearerconfiguration parameters. Furthermore, the UE also uses the receivedsecurity parameters such as NCC to derive a security key for the userplane encryption. After getting ready to receive data from the new CoMPtransmission, the UE responds to the primary point positively with aCoMP Configuration Complete message.

Step 7: After receiving positive acknowledgement from the UE, theprimary point also responds positively to the CoMP Controller with aCoMP Radio Bearer Configuration Response message. The CoMP Radio BearerConfiguration Response message may include a security key K_(eNB)* forthe secondary point. The security key K_(eNB)* of a secondary point isderived based on the security parameter NCC, a UE related securityparameter Next Hop (NH) and the information related to the secondarypoint's identity. It should be noted that the security parameter NCC isthe same as the one sent to UE in Step 5.

Step 8: The CoMP Controller sends a CoMP Radio Bearer ConfigurationRequest message to the secondary point. The CoMP Radio BearerConfiguration Request message contains the information of the requiredRRM/QoS parameters for a subset of an at least one radio bearers to betransmitted by the secondary point and the security key K_(eNB)* of thesecondary point. Furthermore, the CoMP Radio Bearer ConfigurationRequest message sent to the secondary point may comprise otherconfiguration parameters of the subset of an at least one radio bearerto be transmitted by the secondary point. The secondary point uses thereceived K_(eNB)* directly to derive an encryption key K_(U-enc) for theinvolved radio bearers.

Step 9: After storing the received parameters and configuring the radiobearers successfully, the secondary point responds positively to theCoMP Controller with a CoMP Radio Bearer Configuration Response message.

Step 10: The CoMP Controller sends a Path Switch Request message to MMEto inform that a CoMP transmission is established for the involved UE,hence its data packets should now be sent to the CoMP Controller.

Step 11: The MME sends a User Plane Update Request message to theServing Gateway containing the address of the CoMP Controller.

Step 12: The Serving Gateway starts sending data packets of the involvedUE to the CoMP Controller using the newly received address. A User PlaneUpdate Response message is sent back to the MME.

Step 13: The MME confirms the Path Switch Request message with the PathSwitch

Response message.

After the radio bearer management process described above, the CoMPcontroller distributes data packets of EPS bearers to the primary pointand the secondary point respectively. As shown in FIG. 7, the downlinkdata may be sent from SGW to the CoMP controller first. Because theprocess described above has already added the secondary point into theCoMP transmission, the CoMP controller distributes the downlink data toboth the primary point and the secondary point based on the radiobearers handled by each point respectively. Subsequently, data packetsare sent from multiple points (e.g., primary point and secondary point)to the UE.

FIG. 8 illustrates a simplified block diagram of a CoMP controller 800that can be used to implement the radio bearer management method inaccordance with an embodiment. The CoMP controller 800 includes a memory820, a processor 830, a storage unit 840, network interface inputdevices 850, network interface output devices 860 and a data bus 870. Itshould be noted that this diagram is merely an example of a controller,which should not unduly limit the scope of the claims. Many otherconfigurations of a controller are within the scope of this disclosure.

The CoMP controller 800 may be a physical device, a software program, ora combination of software and hardware such as an Application SpecificIntegrated Circuit (ASIC). In accordance with an embodiment, when thecomputer receives a media file through the network interface inputdevices 850, the processor 830 loads the media file into the storageunit 840. According to an embodiment where the advanced media previewmethod is implemented as a software program, the process 830 loads thesoftware program from the storage unit 840 and operates it in the memory820. When the processor 830 performs the steps of FIG. 7, the processor830 sends the radio bearer management information to other networkentities through a network interface output devices 860. It should benoted that the controller 800 may be located at the primary point. Inaddition, if the controller 800 is embedded in the primary point, somesteps of FIG. 7 (e.g., steps 4-7) may be omitted. Alternatively, thecontroller 800 may be located at the secondary point. Furthermore, thecontroller 800 may be located at other network entities such as MME orSGW. Moreover, one skilled in the art will recognize that the controller800 may be a standalone entity wirelessly coupled to other entities of awireless communication system.

In an example embodiment of the invention, the controller is configuredto send the downlink data of a first radio bearer to the primary point;and send the downlink data of a second radio bearer to one or more firstsecondary points. The one or more first secondary points are capable ofscheduling downlink data transmission to the terminal deviceindividually. The terminal device is configured to receive the downlinkdata of the first radio bearer from the primary point, and to receivethe downlink data of the second radio bearer from the one or more firstsecondary points.

As shown in FIG. 9, in accordance with an example embodiment of theinvention, the primary point in the multiple point transmission systemincludes a processor to determine that a reconfiguration is required forthe multiple point transmission system. The processor generates a CoMPConfiguration Request message and sends the message through atransceiver to a UE. The CoMP Configuration Request message may includethe identities of the involved points, radio bearers and EPS bearers.The CoMP Configuration Request message may further include theassociated radio bearer configuration parameters and some specificsecurity parameters such as Next hop Chaining Counter (NCC).

Although embodiments of the present invention and its advantages havebeen described in detail, it should be understood that various changes,substitutions and alterations can be made herein without departing fromthe spirit and scope of the invention as defined by the appended claims.It should also be understood that in some example embodiments, numberedsteps are used just to facilitate the description and the step numbersdo not suggest an order or procedural steps.

Moreover, the scope of the present application is not intended to belimited to the particular embodiments of the process, machine,manufacture, composition of matter, means, methods and steps describedin the specification. As one of ordinary skill in the art will readilyappreciate from the disclosure of the present invention, processes,machines, manufacture, compositions of matter, means, methods, or steps,presently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein may be utilized according tothe present invention. Accordingly, the appended claims are intended toinclude within their scope such processes, machines, manufacture,compositions of matter, means, methods, or steps.

What is claimed is:
 1. A method for operating a multiple pointtransmission system, the method comprising: reconfiguring the multiplepoint transmission system according to an updated configuration of an atleast one radio bearer between an at least one transmission point and aterminal device, wherein the configuration of the at least one radiobearer is updated according to operating condition information of theterminal device; and communicating with the terminal device using thereconfigured multiple point transmission system.
 2. The method of claim1, further comprising: receiving, by a primary point, the operatingcondition information from the terminal device; and communicating, bythe primary point, the operating condition information to a networkentity, wherein the network entity is a controller communicating withthe primary point.
 3. The method of claim 1, wherein the configurationof the at least one radio bearer is updated through one or more of:establishing configurations for a subset of the at least one radiobearer as new radio bearer; modifying existing configurations for asubset of the at least one radio bearer; and establishing configurationsfor a subset of the at least one radio bearer as new radio bearer andmodifying existing configurations for a subset of the at least one radiobearer.
 4. The method of claim 1, wherein the configuration of the atleast one radio bearer is updated through one or more of: adding datatransmission of a subset of the at least one radio bearer on onto afirst point; removing data transmission of a subset of the at least oneradio bearer from a second point; and adding data transmission of asubset of the at least one radio bearer on onto a first point andremoving data transmission of a subset of the at least one radio bearerfrom a second point.
 5. The method of claim 1, wherein reconfiguring themultiple point transmission system according to the updatedconfiguration of the at least one radio bearer comprises: determining aset of parameters for a wireless communication point according to theupdated configuration of the at least one radio bearer, wherein thewireless communication point is for communicating with the terminaldevice; sending a first message to the wireless communication pointindicating the set of parameters and requesting the wirelesscommunication point to form the reconfigured multiple point transmissionsystem at least according to the set of parameters when the set ofparameters is acceptable to the wireless communication point.
 6. Themethod of claim 5, wherein reconfiguring the multiple point transmissionsystem to form a reconfigured multiple point transmission systemaccording to the updated configuration of the at least one radio bearerfurther comprises: informing a primary point by a second messageindicating information for reconfiguring the multiple point transmissionsystem.
 7. The method of claim 5, wherein reconfiguring the multiplepoint transmission system to form a reconfigured multiple pointtransmission system according to the updated configuration of the atleast one radio bearer further comprises: informing the terminal deviceby a third message indicating information for reconfiguring the multiplepoint transmission system.
 8. The method of claim 5, whereinreconfiguring the multiple point transmission system to form areconfigured multiple point transmission system according to the updatedconfiguration of the at least one radio bearer further comprises:informing the wireless communication point by a fourth messageindicating information for reconfiguring the multiple point transmissionsystem.
 9. The method of claim 6, wherein the second message comprises:identities of the radio bearers; identities of associated evolved packetsystem bearers; identities of the wireless communication points; andoptionally comprises reconfiguration parameters of the radio bearers.10. The method of claim 6, wherein informing a primary point by a secondmessage indicating information for reconfiguring the multiple pointtransmission system further comprises: receiving a response to thesecond message from the primary point, wherein the response to thesecond message comprises a first security parameter.
 11. The method ofclaim 7, wherein the third message comprises: identities of the wirelesscommunication points; identities of the radio bearers; identities ofassociated evolved packet system bearers; and optionally comprisesreconfiguration parameters of the radio bearers and a second securityparameter.
 12. The method of claim 7, further comprises: the primarypoint sending a fifth message with a first security parameter uponreceiving a positive response to the third message from the terminaldevice.
 13. The method of claim 8, wherein the fourth message comprises:a first security parameter; and configuration parameters of a subset ofthe at least one radio bearer, wherein the subset of the at least oneradio bearer will be transmitted by the wireless communication point.14. A multiple point transmission system comprising: a primary point andan at least one secondary point, wherein at least one of the primarypoint and the at least one secondary point is configured to: reconfigurethe multiple point transmission system according to an updatedconfiguration of an at least one radio bearer between an at least onetransmission point and a terminal device, wherein the configuration ofthe at least one radio bearer is updated according to an operatingcondition information of the terminal device; and communicate with theterminal device using the reconfigured multiple point transmissionsystem.
 15. The multiple point transmission system of claim 14, whereinthe at least one of the primary point and the at least one secondarypoint is further configured to retrieve data from a controllercommunicating with the primary point and the at least one secondarypoint.
 16. The multiple point transmission system of claim 14, whereinthe primary point is further configured to be wirelessly coupled to theterminal device and to inform the terminal device regarding the updatedconfiguration of the at least one radio bearer associated with themultiple point transmission system; and the at least one secondary pointis further configured to be wirelessly coupled to the terminal device,wherein at least one of the at least one secondary point is capable ofscheduling downlink data transmission to the terminal deviceindividually.
 17. The multiple point transmission system of claim 14,wherein a controller for updating the configuration of the at least oneradio bearer according to operating condition information of theterminal device is located at the primary point.
 18. The multiple pointtransmission system of claim 14, wherein a controller for updating theconfiguration of the at least one radio bearer according to operatingcondition information of the terminal device is located at a networkentity.
 19. The multiple point transmission system of claim 14, furthercomprising: a mobility management entity node communicably coupled tothe primary point, wherein a controller for updating the configurationof the at least one radio bearer according to operating conditioninformation of the terminal device is located at the mobility managemententity node.
 20. The multiple point transmission system of claim 14,wherein a controller for updating the configuration of the at least oneradio bearer according to operating condition information of theterminal device is configured to: configure a first radio bearer to betransmitted through the primary point; and configure a second radiobearer to be transmitted through a first secondary point of the at leastone secondary point, wherein the first secondary point is capable ofscheduling downlink data transmission to the terminal deviceindividually.
 21. The multiple point transmission system of claim 20,wherein the terminal device is configured to receive the downlink dataof the first radio bearer from the primary point, and to receive thedownlink data of the second radio bearer from the first secondary point.22. The multiple point transmission system of claim 20, wherein thecontroller is configured to: receive a security parameter from theprimary point; and send the security parameter to the first secondarypoint.
 23. The multiple point transmission system of claim 14, whereinat least one of the at least one secondary point is capable of beingconfigured to receive a first security parameter, and to obtain a secondsecurity parameter for the updated configuration of a subset of the atleast one radio bearer that are to be transmitted by a correspondingsecondary point.
 24. A primary point for operating a multiple pointtransmission system, the primary point comprising: a processorconfigured to determine that a reconfiguration is needed for themultiple point transmission system, wherein the reconfiguration is inaccordance with an updated configuration of an at least one radio bearerbetween at least one transmission point and a terminal device and theconfiguration is updated according to operating condition information ofthe terminal device; and a transceiver configured to inform a terminaldevice by sending a first message regarding the reconfiguration.
 25. Theprimary point of claim 24, wherein the transceiver is further configuredto provide a first security parameter to be used by a secondary pointfor data transmission of at least one radio bearer.
 26. The primarypoint of claim 24, wherein the processor being configured to determinethat a reconfiguration is needed for the multiple point transmissionsystem comprises receiving a message regarding the reconfiguration ofthe multiple point transmission system from a controller.
 27. Theprimary point of claim 25, wherein the transceiver is configured to senda second message to a controller, wherein the second message comprisesthe first security parameter.
 28. The primary point of claim 27, whereinthe second message is sent upon receiving a positive acknowledgement ofthe first message from the terminal device.
 29. The primary point ofclaim 24, wherein the primary point is further configured to: receive anoperating condition information from the terminal device; andcommunicate the operating condition information to a network entity. 30.A multiple point transmission system comprising: a primary point,configured to communicate with a terminal device and to inform theterminal device regarding an updated configuration of an at least oneradio bearer associated with the multiple point transmission system; andat least one secondary point, configured to communicate with theterminal device, wherein at least one of the at least one secondarypoint is capable of scheduling downlink data transmission to theterminal device individually, wherein the multiple point transmissionsystem further comprises a controller, and the controller is configuredto reconfigure the multiple point transmission system according to theupdated configuration of the at least one radio bearer.
 31. The multiplepoint transmission system of claim 30, wherein the controller is locatedat the primary point.
 32. The multiple point transmission system ofclaim 30, wherein the controller is located at a network entity.
 33. Themultiple point transmission system of claim 30, further comprising: amobility management entity node communicably coupled to the primarypoint, wherein the controller is located at the mobility managemententity node.
 34. The multiple point transmission system of claim 30,wherein the controller being configured to reconfigure the multiplepoint transmission system according to the updated configuration of theat least one radio bearer comprises: configure a first radio bearer tobe transmitted through the primary point; and configure a second radiobearer to be transmitted through a first secondary point of the at leastone secondary point, wherein the first secondary points is capable ofscheduling downlink data transmission to the terminal deviceindividually.
 35. The multiple point transmission system of claim 34,wherein the terminal device is configured to receive the downlink dataof the first radio bearer from the primary point, and to receive thedownlink data of the second radio bearer from the first secondary point.36. The multiple point transmission system of claim 34, wherein thecontroller is configured to: receive a security parameter from theprimary point; and send the security parameter to the first secondarypoint.
 37. The multiple point transmission system of claim 30, whereinat least one of the at least one secondary point is capable of beingconfigured to receive a first security parameter, and to obtain a secondsecurity parameter for the updated configuration of a subset of the atleast one radio bearer that are to be transmitted by a correspondingsecondary point.